1. Field of Invention
The invention relates to a liner removal process and, more particularly, a liner removal process for substantially removing an excess portion of a conformal liner formed in a trench while reducing or minimizing damage to a bulk fill material in the trench.
2. Description of Related Art
High dielectric constant (high-k) materials are desirable for use as capacitor dielectrics in future generations of electronic devices. The first high-k materials used as capacitor dielectrics were tantalum oxide and aluminum oxide materials. Currently, hafnium-based dielectrics are expected to enter production as gate dielectrics, thereby replacing the current silicon oxide and silicon oxynitride materials. However, the practical integration of current high-k dielectric materials, currently under evaluation, suffers from various problems. For example, following the conformal deposition of the capacitor dielectric in the capacitor trench, an undesirable recess is formed in the bulk fill material when performing an etching process to remove any excess portion of the capacitor dielectric extending outside the trench and/or beyond the bulk fill material in the trench. The formation of the undesirable recess occurs due to the poor etch selectivity between the capacitor dielectric and the bulk fill material.